Conventionally available dehumidifiers generally comprise, among other, an evaporator, a water receiving tray disposed under the evaporator, a water discharging tank, and a fast coupler in fluid communication with the water discharging tank. When the environmental air passes by the evaporator which has lower temperature than the air, the water vapor contained in the air will be condensed to form water drip and flows into the water receiving tray under the evaporator.
The water can be discharged in many ways. One of the ways is to use the water discharging tank into which the condensed water in the water receiving tray flows. Once the water discharging tank is almost completely filled, the tank will be manually removed and the water contained therein is discharged. In this case, as the volume of the tank is limited, one has to repeatedly to remove and place the tank every 6-8 hours, which is very inconvenient.
Alternatively, the water can be discharge in real time. In this case, an additional drainage pipe is used to connect to the outlet of a drainage coupler. The drainage coupler is located under the water receiving tray and in fluid communication therewith. The condensed water is continuously drained whenever it flows into the water receiving tray. A shortcoming of this approach is that, because the water is discharged by its gravity, it can not be discharged to a position with higher attitude than the drainage coupler. This is undesirable for those who use the dehumidifier in a basement.
There is another approach to discharge the water, i.e, by using a pump. The pump is always mounted below the water discharging tank and communicated between the discharging tank and the fast coupler. However, pump-equipped dehumidifiers available on the market suffer from one or more of the following shortcomings.
In one circumstance, the actuation of the pump is controlled by a micro-switch which, in turn, is controlled to switch on/off by a floater disposed in the discharging tank. The floater is connected with a spring blade of the micro-switch through a connecting rod. When the water rises to a predetermined level, the floater actuates the micro-switch to switch on through the connecting rod. Because the floater is normally made of foam materials and always soaked in the condensed water, the weight of the floater is increased due to water absorption of the foam materials. The sensitivity of the control of micro-switch by the floater is thus decreased. In addition, the spring blade of the micro-switch is prone to become rusty due to the wet environment where the micro-switch locates.
In another case, the pump is directly connected to the water discharging tank through a water pipe. The pump is subjected to blockage and failure when something is unexpectedly entered into the receiving tray and then the discharging tank and finally the pump. Additionally, the pump is always exposed outside, which imposes a high safety challenge because large amount of heat will be generated in operation.
In some other dehumidifiers, the pump is only actuated when two conditions are fulfilled, one of which is switch-on of the micro-switch, and the other is open status of the fast coupler. This is done for purpose of prevention from misoperation. However, it is in the meantime inconvenient for one to actuate the pump.